The present invention relates to an electrical snap or quick-break switch comprising an activating plunger which, when depressed, establishes an operative connection with a return spring, and charges a spring force accumulator coupled to a ferromagnetic anchor. The anchor is mounted to be tiltable about an axis running at right angles to the direction of plunger activation. The anchor forms the jump member of a magnetic clamp arrangement having a permanent magnet and having two switching positions. The movement of the anchor activates at least one movable electric contact. An additional spring force accumulator is provided for the return and the jumping action is initiated in both switching directions by the generation of an air gap between the anchor and its respective abutting surface.
Quick-break switches having a jumping member which is activated merely by a spring have the disadvantage that the contact force in the immediate proximity of the jumping point becomes almost zero. This disadvantage does not occur with quick-break switches in which the jumping member is a component of a magnetic clamp arrangement. There is known, for instance, magnetic clamp arrangements with two permanent magnets firmly attached to the housing, and an adhesion plate (German examined patent spec. No. 1 118 315 and German printed publ. of unexamined patent spec. DE-OS No. 1 911 104); with a permanent magnet fixed to the housing and two adhesion plates (German patent spec. No. 24 45 957 and German printed publ. of unexamined patent specification No. 26 57 231) connected with the jumping member; as well as two adhesion plates fixed to the housing and a permanent magnet connected with the jumping member (German patent spec. No. 1 190 088). In all these known quick-break switches the jumping member executes a rectilinear displacement along the axis of the activating plunger, ergo in the direction of activation. Furthermore, the necessary springs, in particular the return and force accumulation springs are arranged in or at least along the same axis, so that these switches exhibit great structural length or depth.
Only the switch of the prior used type cited at the outset deviates in so far from this principle of construction. There, an anchor mounted tiltable about an axis running at right angles to the activating direction of the plunger is used, as a jumping member. This anchor is operatively connected with the plunger by way of an activating nose, and carries at each of its two ends a resilient electrical contact member. The anchor cooperates with a rod-shaped permanent magnet arranged in parallel to the activating plunger so as to abut with the magnet in each of the two switching positions and executes a tilting movement about a bearing supported in the center of the bar magnet for the purpose of changing the switching positions. Considerable flux leakage is generated in this design of the magnetic clamp arrangement. The attractive force of the permanent magnet is thus only inadequately utilized. A relatively large bar magnet is therefore necessary with a specified contact force. Since the pull-off force required for the separation of the anchor from the bar magnet is subjected to considerable spread between units, a relatively great activating force is required taking into account in addition the tolerances of the various springs still to be added.
An object of the present invention is to produce a quick-break switch of the type cited at the outset, which has a small structural size and requires a relatively small activating force.